1. Field of the Invention
The present invention relates to a system and a method capable of verifying a contactless sensor tag.
2. Description of Related Art
A contactless sensor tag is defined as an electronic device able to identify or read data through radio signals and a reading system can access the sensor tag without any mechanical contact or optical communication. Thus, the communication between the two can be established through radio signals. Such a system is employed by, for example: an EAZY card (used in Taipei Metro Transportation System in Taiwan), a sense-type credit card, a security door locking buckle or a NFC mobile phone utilizes radio frequency identification (RFID) or near field communication (NFC) for exchanging data, thereby being provided with convenience. However, the identification code of a conventional sensor tag is fixed data or remains the same after being ciphered, so the data is very likely to be logged or deciphered and no security is provided.
Taiwan Patent No. 1384405 has disclosed a verification method, in which a reading device is served to send a first verification code to a responding device, and a signal responded by the responding device is analyzed for obtaining the first verification code which is compared with a second verification code generated by the reading device during receiving. Because the first verification code and the second verification code are relevant dynamic values, an anti-faking effect is provided. However, the responding device and the reading device adopted in the conventional verification method are easy to get, so the devices are vulnerable to being counterfeited or deciphered, and there for contraindicated for high security level applications such as financial transactions.
In addition, U.S. Patent Publication No. 20050071231 has disclosed a system including an authorizing entity, the system utilizes a sensor tag to generate a random number and utilizes a database to provide a verification code relevant to the random number, and the authorizing entity verifies whether the sensor tag is real through examining the relevance between the random number and the verification code. Moreover, the Taiwan Patent No. 1325566 has disclosed an improved verification method, in which a variable secret key is adopted to replace the mentioned database for providing the random number and the verification code thereby increasing the difficulty of deciphering. The two mentioned verification systems both utilize a verifying device, instead of the reading device, for the purpose of verification, but the verifying device trusts the reading device and only processes the verification according the data conflict; if someone intentionally logs the verification data and counterfeits a reading device for sending the verification request, the mentioned verification system is unable to identify the invasion.
In view of the above-mentioned disadvantages, the need for a more reliable verification mechanism for contactless sensor tag persists.